Phenolic contents and genome-wide expression profiling of grapevine berries (Vitis vinifera L. ‘Sangiovese’) ripened under two different temperature regimes

High summer temperatures are among the environmental factors that pose serious threats to viticulture in the present and future scenarios of global climate change. Such extremes are expected to affect different aspects of grapevine biology and metabolism. In this work, we studied the effects of two different temperature regimes, on the evolution of main berry compositional parameters and on grapevine genome-wide expression during ripening. Vitis vinifera 'Sangiovese' potted vines were grown, from véraison to harvest, in two air-conditioned greenhouses with high temperature (HT) and low temperature (LT) regimes characterized by 26 and 21°C as average air daily temperature. We determined berry soluble solids, pH, titratable acidity and phenolic compounds as anthocyanins and flavonols during the ripening process. The results indicated that HT regime did not increase sugar accumulation at harvest but contributed to a total acidity reduction. Conversely, changes in growing temperatures greatly impact on grape phenolic composition as the anthocyanin and flavonol contents resulted strongly reduced in HT compared to LT regime. We applied a clustering analysis approach to the obtained genome-wide microarray data to identify those transcripts with a different transcriptional profile when berries were ripened under HT or LT conditions. We found many differential transcripts involved in heat stress response, many stilbene synthase gene family members, and some other transcripts that corroborate our biochemical results.